While intermolecular hole-hopping along the surface of semiconductors is known, there are no previous examples of electron-hopping between molecules on a surface. Herein, we present the first evidence of electron transfer from the photoreduced sensitizer Coumarin-343 (C343) to complex 1, both bound on the surface of NiO. In solution, 1 has been shown to be a mononuclear Fe-based proton-reducing catalyst. The reduction of 1 is reversible and occurs within 50 ns after excitation of C343. Interfacial recombination between the reduced 1((-)) and NiO hole occurs on a 100 μs time scale by non-exponential kinetics. The observed process is the first essential step in the photosensitized generation of H(2) from a molecular catalyst in the absence of a sacrificial donor reagent.

In addition to the already described ligand L 4a , two pyclen-based lanthanide chelators, L 4b and L 4c , bearing two specific picolinate two-photon antennas (tailor-made for each targeted metal) and one acetate arm arranged in a dissymmetrical manner, have been synthesized, to form a complete family of lanthanide luminescent bioprobes: [EuL 4a ], [SmL 4a ], [YbL 4b ], [TbL 4c ], and [DyL 4c ]. Additionally, the symmetrically arranged regioisomer L 4a′ was also synthesized as well as its [EuL 4a′ ] complex to highlight the astonishing positive impact of the dissymmetrical N-distribution of the functional chelating arms. The investigation clearly shows the high performance of each bioprobe, which, depending on the complexed lanthanide, could be used in various applications. Each presents high brightness, quantum yields, and lifetimes. Staining of the complexes into living human breast cancer cells was observed. In addition, in vivo two-photon microscopy was performed for the first time on a living zebrafish model with [EuL 4a ]. No apparent toxicity was detected on the growth of the zebrafish, and images of high quality were obtained.

Lanthanide complexes (Ln=Eu, Tb, and Yb) that are based on a C2 -symmetric cyclen scaffold were prepared and characterized. The addition of fluoride anions to aqueous solutions of the complexes resulted in the formation of dinuclear supramolecular compounds in which the anion is confined into the cavity that is formed by the two complexes. The supramolecular assembly process was monitored by UV/Vis absorption, luminescence, and NMR spectroscopy and high-resolution mass spectrometry. The X-ray crystal structure of the europium dimer revealed that the architecture of the scaffold is stabilized by synergistic effects of the EuFEu bridging motive, π stacking interactions, and a four-component hydrogen-bonding network, which control the assembly of the two [EuL] entities around the fluoride ion. The strong association in water allowed for the luminescence sensing of fluoride down to a detection limit of 24 nM.